Skimmers are small devices that criminals place on top of a bank-card reader to steal information from the card’s magnetic strip. Criminals also hide pin-sized cameras on the machine to record your pin number.

“The loss could potentially be from hundreds of dollars up to hundreds of thousands of dollars,” Sarafian said.

Sarafian said that most people don’t know that the Secret Service has been keeping the public’s money safe for longer than it’s been protecting the president.

“[It] started in 1865, when we were established under the Department of the Treasury,” Sarafian explained.

Sarafian exclusively showed CBS 2 a stash of evidence from real cases. He explained that once you swipe your card, the information is transferred to a blank card, and then a runner uses that to drain your account.

“It can be done in several hours,” Sarafian said.

And it can be done hundreds of times.

Last month, agents made a huge bust at an Upper East Side Capital One Bank, a ring that stole $3 million.

There are several simple things that you can do to protect yourself. To start, you can cover the keypad when you’re typing in your pin number in case there is a camera. You can also try putting your card into the reader and shaking it, so if there’s an overlay it will fall off. Finally, you can just look at the keypad, and if you see something sketchy that doesn’t belong there, just step away.

“I know that I go to the grocery store and get cash back a lot of times to avoid using the ATM,” Steve Segal of the Upper East Side said.

“I change my pin a couple of times a year,” Dan Gearon of the Upper East Side added.

The Secret Service said that it’s everyone from lone actors to organized groups committing the skimming crime. Most recently, several of those arrested have been from Eastern Europe.

How concerned are you — if at all — about being scammed at the ATM machine? Let us know your thoughts and comments in the section below…